P122 External validation of the Picasso Histological Remission Index (PHRI) to assess endoscopic and histological remission and predict long-term outcome in Ulcerative Colitis: A multicentre prospective study

Abstract Background The PICaSSO Histological remission Index (PHRI) is a simple histological index for assessing ulcerative colitis (UC) based only on the presence or absence of neutrophils in lamina propria, superficial and cryptal epithelium (Table 1), which can be implemented artificial intelligence (AI) systems.1 We aimed to externally validate its correlation with endoscopy prognostic value. Methods Patients UC underwent colonoscopy Birmingham, UK using white light+NBI, Milan, Italy, light+BLI/LCI. Participants were followed up 2 years occurrence major adverse outcomes (UC-related hospitalization, treatment change/optimization, need steroids, colectomy) recorded. measured (Spearman coefficient) between scores (PHRI, Nancy [NHI] Robarts [RHI]) endoscopic (Mayo Endoscopic Score [MES]; Ulcerative Colitis Severity [UCEIS], Paddington International virtual ChromoendoScopy ScOre [PICaSSO]). Vice versa, ROC curves plotted assess remission. Outcome analysis at 24 months was performed according Cochran-Mantel-Haenszel method, Kaplan-Meier hazard ratios calculated. Results 159 patients enrolled, 79 NBI cohort 81 BLI/LCI cohort. Demographic characteristics are detailed Table 2. PHRI correlated all regardless type chromoendoscopy. In particular, correlations 0.86, 0.83 0.81 MES, UCEIS PICaSSO, respectively; 0.69, 0.65 0.58 Correlation also similar PHRI, Robarts. 3. area under curve (AUROC) 0.95 (95% CI 0.91-1.00), 0.90-1.00), 0.93 0.87-0.99), respectively. Similarly, AUROCs 0.86 0.78-0.94), 0.88 0.81-0.95) 0.85 0.77-0.94). At survival (Figure Kaplan Meier appeared similar, ratio (HR) histologically active 3.11 1.47-6.57), 2.93 1.36-6.32) 2.19 1.07-4.53) RHI NHI, 2.82 1.54-5.15), 1.54-5.16) 1.54-5.15) Conclusion confirmed PHRI’s endoscopy, performance value two independent cohorts. Neutrophil-only assessment reliable alternative current useful tool AI systems. Reference: 1 Gui X. et al. Gut, 2022